next/master bisection: baseline.login on ox820-cloudengines-pogoplug-series-3

[Ard Biesheuvel]

On Fri, 18 Dec 2020 at 15:00, Russell King - ARM Linux admin
<linux at armlinux.org.uk> wrote:
>
> On Fri, Dec 18, 2020 at 01:48:09PM +0000, Guillaume Tucker wrote:
> > Please see the bisection report below about a boot failure on
> > ox820-cloudengines-pogoplug-series-3.  There was also a bisection
> > yesterday with next-20201216 which landed on the same commit, on
> > the same platform and also with oxnas_v6_defconfig.  I'm not
> > aware of any other platform on kernelci.org showing the same
> > regression.
>
> Ah, I bet I know what's happening.
>
> We test for the presence of VFP by issuing an instruction to read
> FPSID. If VFP is not present, this will raise an undefined instruction
> exception, and we expect to head into the vfp_testing_entry code.
>
> I bet Pogoplug, being an ARM11 MPCore platform, either raises an
> exception here.
>
> We probably need to also rework the code in vfp_init() as well to
> register a temporary hook when reading the FPSID.
>

Thanks for diagnosing that - I wasn't quite sure what was going on.

I will look into this later today.